Effects and feasibility of a preventive intervention in sub-threshold and mild panic disorder: Results of a pilot study.

Background: Panic disorder (PD) is a serious DSM-IV axis I disorder affecting up to 3% of the adult population each year. It is associated with a large burden of disease and extensive economic costs. This study aims to examine the effects and feasibility of the 'Don't Panic' course, a preventive cognitive behavioural intervention in sub-threshold and mild PD. It also compares the effectiveness of two modifications of the course (8 vs. 12 sessions).

Methods: The method used was a quasi-experimental two-group pre-post design with a baseline measurement (T0) and two follow-up measurements. Follow-ups were at the end of the intervention (T1) and six months later (T2). Primary outcome measure was the Panic Disorder Severity Scale-Self Report. A total of 114 participants suffering from panic attacks (mean age 42 years; 78% female) entered the study.

Results: The course participants showed a significant effect on the outcome measures at follow-up. Large effect sizes were found on panic symptoms, on symptoms of agoraphobia and on mental health-related quality of life at T1 and T2. Overall, the course leaders and the participants evaluated the course positively. There were no significant differences in outcome measures between the short and the long version of the course.

Conclusion: The study suggests that people with sub-threshold PD and mild PD could benefit from this preventive intervention and that the intervention might be feasible. Furthermore, the short version could be as effective as the long version.